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For C2D, Set Up Private Docker Registry

Learn how to setup your own docker registry and push images for running algorithms in a C2D environment.
The document is intended for a production setup. The tutorial provides the steps to set up a private docker registry on the server for the following scenarios:
  • Allow registry access only to the C2D environment.
  • Anyone can pull the image from the registry but, only authenticated users will push images to the registry.

Setup 1: Allow registry access only to the C2D environment

To implement this use case, 1 domain will be required:
  • example.com: This domain will allow only image pull operations
Note: Please change the domain names to your application-specific domain names.

1.1 Prerequisites

  • A docker environment running on a Linux server.
  • Docker compose is installed.
  • C2D environment is running.
  • The domain names are mapped to the server hosting the registry.

1.2 Generate certificates

# install certbot: https://certbot.eff.org/
sudo certbot certonly --standalone --cert-name example.com -d example.com
Note: Check the access right of the files/directories where certificates are stored. Usually, they are at /etc/letsencrypt/.

1.3 Generate a password file

Replace content in <> with appropriate content.
docker run \
--entrypoint htpasswd \
httpd:2 -Bbn <username> <password> > <path>/auth/htpasswd

1.4 Docker compose template file for registry

Copy the below yml content to docker-compose.yml file and replace content in <>.
version: '3'
​
services:
registry:
restart: always
container_name: my-docker-registry
image: registry:2
ports:
- 5050:5000
environment:
REGISTRY_AUTH: htpasswd
REGISTRY_AUTH_HTPASSWD_PATH: /auth/htpasswd
REGISTRY_AUTH_HTPASSWD_REALM: Registry Realm
REGISTRY_HTTP_SECRET: <secret>
volumes:
- <path>/data:/var/lib/registry
- <path>/auth:/auth
nginx:
image: nginx:latest
container_name: nginx
volumes:
- <path>/nginx/logs:/app/logs/
- nginx.conf:/etc/nginx/nginx.conf
- /etc/letsencrypt/:/etc/letsencrypt/
ports:
- 80:80
- 443:443
depends_on:
- registry

1.5 Nginx configuration

Copy the below nginx configuration to a nginx.conf file.
events {}
http {
access_log /app/logs/access.log;
error_log /app/logs/error.log;
server {
client_max_body_size 4096M;
listen 80 default_server;
server_name _;
return 301 https://$host$request_uri;
}
​
server {
# Allowed request size should be large enough to allow pull operations
client_max_body_size 4096M;
listen 443 ssl;
server_name example.com;
ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
location / {
proxy_connect_timeout 75s;
proxy_pass http://registry-read-only:5000;
}
}
}

1.6 Create Kubernetes secret in C2D server

Login into the compute-to-data enviroment and run the following command with the appropriate credentials:
kubectl create secret docker-registry regcred --docker-server=example.com --docker-username=<username> --docker-password=<password> --docker-email=<email_id> -n ocean-compute

1.7 Update operator-engine configuration

Add PULL_SECRET property with value regcred in the operator.yml file of operator-engine configuration. For more details on operator-engine properties refer to the operator-engine readme.
Apply updated operator-engine configuration.
kubectl config set-context --current --namespace ocean-compute
kubectl apply -f operator-engine/kubernetes/operator.yml

Steup 2: Allow anonymous pull operations

To implement this use case, 2 domains will be required:
  • example.com: This domain will only allow image push/pull operations from authenticated users.
  • readonly.example.com: This domain will allow only image pull operations
Note: Please change the domain names to your application-specific domain names.

2.1 Prerequisites

  • Running docker environment on the Linux server.
  • Docker compose is installed.
  • 2 domain names are mapped to the same server IP address.

2.2 Generate certificates

# install certbot: https://certbot.eff.org/
sudo certbot certonly --standalone --cert-name example.com -d example.com
sudo certbot certonly --standalone --cert-name readonly.example.com -d readonly.example.com
Note: Do check the access right of the files/directories where certificates are stored. Usually, they are at /etc/letsencrypt/.

2.3 Generate a password file

Replace content in <> with appropriate content.
docker run \
--entrypoint htpasswd \
httpd:2 -Bbn <username> <password> > <path>/auth/htpasswd

2.4 Docker compose template file for registry

Copy the below yml content to docker-compose.yml file and replace content in <>. Here, we will be creating two services of the docker registry so that anyone can pull the images from the registry but, only authenticated users can push the images.
version: '3'
​
services:
registry:
restart: always
container_name: my-docker-registry
image: registry:2
ports:
- 5050:5000
environment:
REGISTRY_AUTH: htpasswd
REGISTRY_AUTH_HTPASSWD_PATH: /auth/htpasswd
REGISTRY_AUTH_HTPASSWD_REALM: Registry Realm
REGISTRY_HTTP_SECRET: <secret>
volumes:
- <path>/data:/var/lib/registry
- <path>/auth:/auth
registry-read-only:
restart: always
container_name: my-registry-read-only
image: registry:2
read_only: true
ports:
- 5051:5000
environment:
REGISTRY_HTTP_SECRET: ${REGISTRY_HTTP_SECRET}
volumes:
- <path>/docker-registry/data:/var/lib/registry:ro
depends_on:
- registry
nginx:
image: nginx:latest
container_name: nginx
volumes:
- <path>/nginx/logs:/app/logs/
- nginx.conf:/etc/nginx/nginx.conf
- /etc/letsencrypt/:/etc/letsencrypt/
ports:
- 80:80
- 443:443
depends_on:
- registry-read-only

2.5 Nginx configuration

Copy the below nginx configuration to a nginx.conf file.
events {}
http {
access_log /app/logs/access.log;
error_log /app/logs/error.log;
server {
client_max_body_size 4096M;
listen 80 default_server;
server_name _;
return 301 https://$host$request_uri;
}
​
server {
# Allowed request size should be large enough to allow push operations
client_max_body_size 4096M;
listen 443 ssl;
server_name readonly.example.com;
ssl_certificate /etc/letsencrypt/live/readonly.example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/readonly.example.com/privkey.pem;
location / {
proxy_connect_timeout 75s;
proxy_pass http://registry:5000;
}
}
​
server {
# Allowed request size should be large enough to allow pull operations
client_max_body_size 4096M;
listen 443 ssl;
server_name example.com;
ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
location / {
proxy_connect_timeout 75s;
proxy_pass http://registry-read-only:5000;
}
}
}

Start the registry

docker-compose -f docker-compose.yml up

Working with registry

Login to registry

docker login example.com -u <username> -p <password>

Build and push an image to the registry

Use the commands below to build an image from a Dockerfile and push it to your private registry.
docker build . -t example.com/my-algo:latest
docker image push example.com/my-algo:latest

List images in the registry

curl -X GET -u <username>:<password> https://example.com/v2/_catalog

Pull an image from the registry

Use the commands below to build an image from a Dockerfile and push it to your private registry.
# requires login
docker image pull example.com/my-algo:latest
​
# allows anonymous pull if 2nd setup scenario is implemented
docker image pull readonly.example.com/my-algo:latest

Next step

You can publish an algorithm asset with the metadata containing the registry URL, image, and tag information to enable users to run C2D jobs.

Further references

Last modified 7mo ago